This invention relates to a corrosion inhibited chloride salt formulation. More particularly, this invention relates to chloride salt composition such as calcium chloride, magnesium chloride, sodium chloride and potassium chloride and blends thereof containing a corrosion inhibitor composition. These compositions are useful not only as roadway deicer but also in various other applications in which chloride salts, in solution or as a solid, provide an important function in such applications as freezeproofing, refrigeration, dust control, concrete additive and the like in which the chloride salts are used and in which corrosion presents a direct or indirect problem.
Chloride salt solutions of calcium, magnesium, sodium and potassium sodium have been used for deicing of road and roadway structures for many years. Sodium chloride is readily available and in inexpensive. However, the use of sodium chloride or the primary deicer has several disadvantages; it has an adverse effect on roadside vegetation and the groundwater, and it severely corrodes roadside barriers, bridges and the like, as well as the vehicles that drive over them and the equipment used to apply them. This adds to the overall costs of using sodium chloride. Thus a search had been ongoing for some time to replace sodium chloride as a deicer with a less corrosive material.
Other salts as the primary deicing agents have been suggested, but either they are too expensive, unavailable in quantity, they are also substantially corrosive and / or do not function efficiently in the proper concentration and/or at the desired deicing temperature ranges.
Calcium chloride, an effective deicer and freeze depressant for various active uses and, is less corrosive than sodium chloride, but it is still corrosive to metals as are the other chloride salts, e.g., magnesium and potassium. The use of calcium chloride as a deicer composition is advantageous because it generates heat when it comes in contact with solidified water, such as snow and or ice, thereby further promoting the deicing process. Likewise, chloride salts, calcium and magnesium in particular, are used for a variety of applications such as freezeproofing, dust control, concrete additives, to name a few, where corrosion may be a problem. Direct and indirect contact of chlorides with application equipment, processing equipment and various other metal components or metal structures has always been a concern. Therefore, the formulation of an inexpensive, less corrosive chloride provides an opportunity in many areas where chlorides are used today.
Various corrosion inhibitors have been tried for chloride salts. For example the use of chromates as corrosion inhibitors for chloride brine solutions is known; however, the use of chromates is being discouraged because of the adverse impact they have on the environment. The use of nitrites such as sodium, calcium, potassium and the like, has also been suggested, but a high level of the nitrite content with the chloride salt is required as a corrosion inhibitor making nitrite an impractical additive, particularly for large scale applications. Other known corrosion inhibitors include phosphates, borates, amines, molybdates, hydroquinone, gluconates and impure sugar sources such as molasses. However, none of the known prior art formulations are regarded as sufficient to inhibit corrosion to the desired practical and environmentally desired level.
In accordance with the invention, I have discovered that an inexpensive, non-corrosive compositions of chloride salts, primarily the chloride salts of calcium, magnesium, sodium and potassium, and preferably calcium chloride salts can be prepared comprising an aqueous solution of such salts and honey. Solid form compositions of the chloride and honey are also contemplated. In the corrosion inhibited compositions of the invention, proportion of up to about 50% by weight of honey based on the weight of the chloride salt can be employed. However, for most applications, the honey content in the formulation of the invention comprises from about 500 to about 110,000 ppm based on the weight of the salt and preferably about 4000 to 100,000 ppm. The non-corrosive formulations may comprise as little as 0.5-2.0% by volume of honey and still comply with criteria of a 70% reduction in corrosion with respect to that of sodium chloride solutions without corrosion inhibition.